The present invention relates to hydraulic cylinder apparatus in general and more particularly to a structure for mounting the housing of a hydraulic cylinder or other actuator on a support plate, with a portion of said cylinder projecting through the support plate.
The invention relates more specifically to apparatus such as hydraulic actuator apparatus capable of operating a mechanism at a remote location by way of for example, a master cylinder connected to a slave cylinder installed at the remote location, a flexible conduit interconnecting the master cylinder and the slave cylinder. It is known to provide such hydraulic actuator apparatus for actuating, for example, the release mechanism of a friction clutch. In British patent specification No. 1,539,879, and in co-pending application for U.S. Patent, Ser. No. 911,477, and in co-pending application for U.S. Patent, Ser. No. 344,495, filed Feb. 1, 1982, there are disclosed preassembled friction clutch hydraulic control apparatus, which are prefilled with hydraulic fluid prior to shipment to a motor vehicle manufacturer for installation on a motor vehicle.
For the purpose of installing such apparatus on the motor vehicle both the master cylinder and the slave cylinder are provided with a mounting flange integrally cast or molded with the cylinder housing and disposed peripherally to the cylinder housing at some intermediary location between the ends of the housing. The mounting flange has mounting apertures, or is provided with ears or lugs having mounting apertures for installation of the cylinder on a support plate or panel or on a support bracket. The master cylinder is generally installed by being mounted in an aperture in a bulkhead, such as the vehicle floorboard, with an end of the cylinder housing projecting on one side of the bulkhead and the other end of the housing projecting on the other side of the bulkhead. The bulkhead is provided with an opening through which the cylinder housing is passed with a plurality of mounting holes disposed around the periphery of the opening. The mounting holes in the flange of the cylinder housing, or in the mounting lugs, must be aligned with the mounting holes in the bulkhead or floorboard, and the cylinder housing securely attached in position by means of appropriate bolts, or other fasteners, passed through the aligned mounting holes. Similarly, the slave cylinder is generally supported through an opening in the clutch housing itself, or on a lug or bracket attached to the clutch housing or integrally cast with the clutch housing. The slave cylinder housing is attached in position by way of bolts passed through aligned mounting holes in the clutch housing or bracket and in the cylinder housing mounting flange or lugs.
Other mounting arrangements for master and slave cylinders have been developed in the past for simplifying the installation of such hydraulic apparatus on the assembly line of a motor vehicle manufacturer, as disclosed for example in the aforesaid British patent specification, in the form of a snap ring retainer for the slave cylinder and of a push-and-rotate fastening arrangement for the master cylinder. The master cylinder is mounted through a square opening in the bulkhead. The housing of the master cylinder is provided with a substantially square flange spaced apart from a circular flange. The square flange is of a size permitting passage thereof through the square opening in the bulkhead. A resilient gasket is installed between the two flanges and is compressed when the square flange is pushed through the square opening in the bulkhead and the housing rotated approximately 45.degree. around its longitudinal axis, thus causing the tips of the square flange to engage the rear surface of the bulkhead proximate the square opening and hold the cylinder housing in position in view of the diagonal of the square flange having a length greater than the distance between opposite sides of the square opening. However, in such an arrangement only frictional forces resulting from the compression of the resilient gasket, and causing engagement of the square flange tip surface with the corresponding surface of the bulkhead, prevent rotation of the master cylinder housing relative to the square mounting opening, as no other positive lock is provided.
The present invention is an improvement on the master cylinder mount structure disclosed in the aforesaid British patent specification and corresponding applications for U.S. Letters Patent.